Originally Posted by Tellie
Unfortunately, as far as I know at this point, the PUR/Katadyn membranes are only made by Katadyn and yes they are proprietary and pricey.
I can assure you that Katadyn is not a big enough company to be manufacturing their own R/O membranes. The sizes and fittings sure look like a match for standard Dow Filmtec membranes.
Are you SURE they are proprietary? Or do they just tell you to "only use genuine, etc,etc."
Spectra is now owned by Katadyn, and I KNOW those are industry standard membranes.